It is fascinating to reflect on the great impact of the PC on society. The PC is clearly capable of doing a whole lot more than what we use it for. Essentially, for many the PC became a replacement for the typewriter, and it is still largely a word processor. The other initial application that drove PC adoption was the spreadsheet. Then it also became a presentation creation tool. Over time, email was introduced and, even more recently, Web browsing. Web browsing, in turn, is giving rise to online shopping and replacing encyclopedias as our primary information resource. But, overall, there are still very few uses for these powerful machines by the average user.
We are now going through a phase where the capabilities of different types of devices are converging. Devices rely on common protocols and are often connected via the Internet, and the services offered are becoming more portable and accessible wherever we are and whenever we need them. We now have PCs, cellphones, TVs, iPods, PDAs, and camera phones relying on the Internet, complemented by communication networks such as the cellular networks, Bluetooth, and Wi-Fi. Services range from unified messaging and VOIP to entertainment.
With these trends toward greater connectedness and mobility, perhaps the most central problem is how to make text entry possible on small, portable devices. The success of email, SMS, and instant messaging on portable devices and user patterns already established on the PC make an efficient text-entry system a must for broad adoption of smaller, mobile devices.
In this direction, the RIM pagers (the Blackberry devices) are prime examples of a well-designed portable device. It is simply an excellent email machine, and for many this immediate access to email becomes highly addictive. A great deal of the success of this type of device relies on its small keyboard, which allows for two-thumb typing. This typing is quick and easy to learn since it relies on the same basic organization as the regular typewriter/PC keyboard.
For cellphones there is the T9 method by Tegic (U.S. Pat. No. 5,818,437 and other pending patents; T9 text input software Copyright 1999-2002; Tegic Communications, Inc.); cf. [22], [23].
For PDAs, the preferred method for text entry seems to be using a touch screen combined with “graffiti” entered using a stylus or tapping a keyboard with the stylus. Recognition of handwriting is also widely used.
A solution to the text entry problem for small portable devices should ideally address the following capabilities:                support touch-typing and rapid text entry;        easy-to-learn and consistent with standard keyboards;        easily extensible to include new words and new contexts;        small enough for portability and easy integration with mobile devices;        easy corrections of typos and minor mistakes; and        support auto-completion.        
These goals are addressed by the invention described herein.